Exposure to some toxic metals may be linked to diseases of the brain system or general mental health. Depression is one of the best-known conditions in this field, and in the context in which we live, more and more patients are suffering from its symptoms. The pandemic and the consequent restrictions are deteriorating the mental well-being of people of all ages, some of them diagnosed with depression.
This is also influenced by the accelerated pace of life in the West, increasingly widespread throughout the planet. The stress generated by work, studies, family and economic burden or other aspects such as lack of physical exercise and the need for a healthy diet can work against people who want to promote normal cognitive function.
Supplements for depression
A Korean national cohort study has shown that higher intakes of vitamins A, B1, and B3 might have the ability to reduce the risk of depression associated with heavy metal exposure. The research analyzed data from 16,371 people who participated in the Korea National Health and Nutrition Examination Surveys (KNHANES) between the years 2009 and 2017, excluding the years 2014 and 2015.
The aim of the study was to determine the relationships between the prevalence of depression, dietary vitamin intake, and serum levels of heavy metals (mercury, cadmium, and lead). In this regard, an increase in serum cadmium (Cd) was found to be associated with an increased risk of depression, but this could be alleviated by an increase in vitamin intake.
The research team looked at both daily vitamin intake and food intake, using a 24-hour dietary recall. In addition, the subjects completed a semi-quantitative food frequency questionnaire that analyzed their intake of 63 food items.
Study Results
The researchers have published that the level of Cd in serum was significantly higher in subjects with depression, as reflected in their results. Exactly, the geometric mean serum cadmium level was 1.11 ug/l in depressed participants and 0.81 ug/l in non-depressed participants.
“An increase in serum Cd was associated with an increased risk of depression, and surprisingly, the risk of depression was found to decrease rapidly when intake of vitamin B1, B3, or total vitamin A increased,” the study authors confirmed. These findings support data that previously pointed to the effects of heavy metal and vitamin intake in the diet, related to the pathogenesis of depression.
In contrast, compared to participants without depression, their geometric mean intake of vitamin B1, B3 and A was 1.26 mg, 13.82 mg and 481.40 mg, respectively. While those with depression had a lower intake (0.99 mg, 10.80 mg and 392.76 mg).
Vitamins against depression
According to the results, the risk of depression decreased as vitamin intake increased. Specifically, a twofold increase in daily intake of vitamin B1, B3 or A reduced the risk of depression by 17%, 20% and 8%, respectively. “The result shows that a higher daily intake of dietary vitamins could protect the public against depression,” the research team stated.
However, the authors believe that more study is needed to reduce the risks posed by heavy metals. “Future studies could more fully determine the effects of daily dietary vitamin intake on depression,” they added. Furthermore, while other studies reported that elevated serum magnesium and lead levels were associated with depression, this study found no evidence for these associations.
The neurological impact of cadmium
The mechanisms by which serum cadmium is related to neuropsychiatric disorders are not well understood, however, researchers have pointed to some possible explanations. First, Cd can cross and break the blood-brain barrier and thus could induce oxidative stress and mitochondrial dysfunction. It is even possible to cause apoptosis of neuronal cells in brain tissue.
Second, it can negatively affect the central nervous system by triggering vascular damage through endothelial oxidative stress. This is a risk factor for depression. Finally, vitamin B deficiency is known to play a role in the development of depression, so increasing it through diet or supplementation could be a correct and natural option.
Conclusions
The researchers say that these results show that vitamin B1 intake is inversely associated with depression. This supports the result obtained in a previous study, in which vitamin B1 supplementation for 6 weeks reduced depressive symptoms in older women.
On the other hand, there are other studies that have also reported the benefits of supplements based on vitamin B1. These are nutrients with the ability to reduce depressive symptoms and improve cognitive function in patients with geriatric depression. Furthermore, in a case report, supplementation was successful in reducing depressive symptoms in a 50-year-old man admitted to a psychiatric clinic.
It should be noted that the Korean study is the first that has been carried out in this area on a large scale. It has reported the effects of dietary vitamin intake and serum heavy metal levels on depression in a representative sample.
